Це відео не доступне.
Перепрошуємо.
Solar Eclipse Maths and the Cosmic Coincidence of the Saros Cycle
Вставка
- Опубліковано 19 бер 2015
- There was a solar eclipse on the 20 March 2015 and so I thought I'd make a quick video of the mathematics behind predicting eclipses. I now regret that decision.
EDIT: I over-simplified the elliptical orbit of the moon but not putting the Earth at one of the foci, which messes with the closest and nearest points at 3:40. Elliptical orbits are not that simple.
NASA pages on the moon's orbit and the Saros cycle:
eclipse.gsfc.na...
eclipse.gsfc.na...
Photograph of the total eclipse is copyright Anthony Ayiomamitis and used with his kind permission.
www.flickr.com...
The paper on the long-term instabilities of planetary orbits is here:
www.nature.com/...
Fred Espenak is the eclipse dude:
www.mreclipse.c...
Music by Howard Carter
Design by Simon Wright
MATT PARKER: Stand-up Mathematician
Website: standupmaths.com/
New book: makeanddo4D.com/
Nerdy maths toys: mathsgear.co.uk/
"Unfortunately, it's not that simple…"
That is going to resonate it my dreams for the rest of my life…
"And now for something completely different."
***** ....a man with three buttocks?
+Lawrence Calablaster No, but here's a stripèd green rabbit... with two butts.
41.media.tumblr.com/b2ade7123550c879606c7c658e3bd62a/tumblr_n6ig7wDAaj1rn3viqo1_540.png
+Lawrence Calablaster and two anuses - or anii :P
Another credit grabber video.
Saros Cycle was invented by Babylonian astronomy, the land where Abraham born.
Saros cycle is accurate and still used by NASA today and integrate in the software.
Same people who said that the solar eclipse is not the cause of moon blocking the sun.
So, which one you should believed NASA and most western scientist who used saros cycle or the one who invented the saros cycle?
Moon can be seen even in the day, we should see moon hours before eclipse.
That is why Babylonian astronomy make sense to me.
Is it weird that I think Matt has the best voice ever? He could talk about making toast for 15 minutes and I'd listen. If I made an animated show, I'd need to get him to do voice-over.
Don't tempt me: I'm a big fan of toast.
+standupmaths University of Leeds did, I believe, develop a formula for "perfect" toast several years ago... of course that study was commissioned by a British(?) butter brand, so I am unsure if the formula validates against empirical evidence. Personally have not looked into this formula, as I (lately, anyway) prefer my toast toasted in melted butter, removing the need to spread said dairy product onto the toast as it sits there on the plate already cooling. Of course even cool toast is better than no toast, but that would likely be a subject for a whole new channel. Still, a standupmaths "Matt explains toast" video would be quite appreciated by all fans of said staple, with or without delving into Leeds U's formula for "perfect" toast. As Bartholomew Bartelbuss, famous toast fancier of the last century, was wont to shout: "Give me toast! Or give me pizza at least...". Excuse me, now it is time to make some toast. Cheers!
+Molly Ringwald he has a voice for being a doctor who
Yuzuru A but I think he's too funny to be a serious character
+standupmaths Do a toast video! DO IT! NOOOOOOOWWWWWW!!!!!!!!
3:38 The Earth is actually at one of the foci of the ellipse, not in the center, because of Kepler's first law of planetary motion. That way we only have one closest point (periapsis) and one farthest point (apoapsis) per orbit of the moon.
Yes, putting the Earth on the middle of the eclipse and not at a focus point is my big regret for this video. I'll make a note of that in the description!
+standupmaths I would put an annotation that says "the diagram shows two apogees and perigees but only one of each is possible" or something similar.
Apogee and perigee are specific to orbits around the earth. Perihelion and aphelion to orbits around the sun. Apoapsis and periapsis are general, and refer to similar points in any orbit around a central attracting body. The moons of Jupiter have perijove (at delightful term) and apojove (nearly as delightful). Apoapsis and periapsis are not wrong, but perigee and apogee are more common when speaking of orbits around the geoid.
It was a decent effort. Why not retract it and replace it with something better? You have a very loyal audience and we will understand.
@@standupmaths Earth and the Moon orbit about their barycentre (common center of mass), which lies about 4,600 km (2,900 mi) from Earth's center (about 72% of its radius). That is to say, the barycentre is within the earth in the figure (which Matt did repeatedly emphasize is NOT to scale). So in a more to scale drawing, the earth would be only ever so slightly displaced to one side. And since the earth rotates on its axis, the barycentre also rotates around that axis once a day. Or should we say the axis rotates about the barycentre once a day?
Matt's worst nightmare:
"Fortunately, it *is* that simple!"
"Unfortunately, it's not that simple."
*NOTHING* about the Moon's orbit is simple.
The late veteran astronomer and popularizer of astronomy, Sir Fred Hoyle, once wrote that a very strong case could be made that the circumstances of our natural satellite's orbit are responsible for much of the development of advanced mathematics!
Pre-*cise*-ly because, "it's never that simple."
And those who got the bug for attempting to explain it, actually *made* some of those mathematical advancements.
And as rankling as this video might be to some, it actually gives an excellent sense of that complication.
[Major kudos, Matt!!]
That said, the many types of month (and there *are* more than the 3 given here), are an indication of some of that complication.
• The month of phases (which Matt is calling the "lunar" month, which is pretty redundant, and undescriptive) is called, the synodic month.
= 29.530589 days
• The month between nearest approaches to Earth (which are the Moon's perigees) is called the anomalistic month, because the "anomaly" of an orbiting body is the angle where it stands in its orbit, measured past its last nearest approach point.
= 27.554550 days
• The month between the Moon's ascending node crossings of the ecliptic plane (plane of Earth's orbit) is called the draconic month.
= 27.212221 days
• The month between when the Earth-Moon line returns to the same direction in space, is called the sidereal month; "sidereal" meaning, referred to the distant stars. *That* is the Moon's true orbital period, and *that* is the month Matt should have used (rather than the anomalistic month), from about 4:00 to about 4:50, to explain the ≈2 day difference required for the Moon to go from completing an orbit to lining up with the Sun again.
= 27.231662 days
• There’s also a tropical month, but it isn’t needed for any of this.
= 27.231582 days
Oh, and when he first mentions and shows the Moon’s orbit as elliptical rather than circular, the graphic of that is incorrect - the Earth is *not* at the center of that ellipse; it’s at one focus. So there’s only one perigee and one apogee in an orbit; not two of each. [Although I see he’s already made a note of this in the description.]
The only other tidbit I would add to this quite excellent video, is that the saros cycle can be either 18y 11d 8h or 18y 10d 8h, depending on the fall of leap days. [NB. If there's a "Gregorian exception year" during a saros, it can be 18y 12d 8h; but that happened last in 1900, and won't again until 2100.]
In any case, it is always 6585d 8h.
ffggddss why????????
Person: what's one plus one?
Me: 2
Matt: unfortunately it's not that simple
5,000SubscribersNoVideos why?????
Ahhhhh! The earth not being at the focus of the ellipse at 3:36 is driving me crazy!
the solar eclipse of 2015
very nice clouds. I see those often. don't usually go out to watch them
Unfortuanatly, It's not that simple.
There's the Saros you mentioned here, and there's also the inex (358 synodic months or about 29 years), which has the property where if an eclipse happens in saros N and Saros N+1 is still active, there will be an eclipse in that one about 29 years later. In fact, given the solar/lunar eclipses with saros and inex both 0 (all the math works out for lunar eclipses too) you can identify each eclipse with a unique saros/inex pair!
Sure the diagram is not to scale, but putting the Earth at the center of the ellipse rather than at one of its focal points is inexcusable.
it annoys me uguggghghgg
THANK YOU, THANK YOU, THANK YOU. It's PATHETIC. I'm not going to judge some random person walking down the street for not knowing this stuff, but if you're going to make a video you're subject to a different standard. PATHETIC, PATHETIC, PATHETIC.
0:39 To scale. Sun=Moon=Earth=~1/3 Matt Parker's head.
I'm here after Annular Solar Eclipse on December 26, 2019 here in the Southern Philippines.
So lucky in my lifetime I saw it once again.
"the probability of that happening is literally astronomical" - but a statistical certainty.
That is incorrect. When the chance of something happening is given as 1, this means there is no other chance of other things happening. The only thing that can happen is that given thing, now, and forever. The statistical certainty alluded to in this case is really bellied by the hidden assumption / meaning .... that EVENTUALLY it will happen. The number IS on the die, the card is in the deck.
+Hythloday71 when the statistical chance of something happening eventually is 1 is what i think he meant
Unfortuanatly, It's not that simple.
I searched "eclipse but it's not that simple" because I wanted to find this video again, and it did show up :P
I learned something today. The eclipse I'm hoping to see in 2017 is one Saros cycle after the one I saw in 1999. I know this doesn't really make it 'the same eclipse', but it kind of feels like that, which is cool! Great video (apart from the shape of the Moon's orbit, which was wrong. The Earth should be at a focus!)
I planning to do the 2009 - 2027 double as well!
And yes, I did mean to put the Earth over on a focal point, but that was sacrificed in the making of the animations.
standupmaths Thanks for replying! It's cool that you take the time to do that. And the ellipse thing is such a minor quibble that it doesn't affect the message. Your videos are great, and I'm going to show this one to my son. He was watching the eclipse the other day at school, so carpe diem :)
That orbital diagram made me want to cry. Not how elliptical orbits work at all (but I'm sure you know that already)
+Debated Nothing Clearly Matt is not a KSP player.
+Debated Nothing It made me facepalm, cry, and scroll down to read the comments..
+Debated Nothing Yes, it is written in the description. Every time someone puts Sun to the center of an ellipse, little Kerbal dies in the most horrible way imaginable. :D
I'm glad to see that other people caught that. XD
Debated Nothing "In fact, there's pretty much nothing in this video, that's to scale."
-Matt Parker
I have not read all the comments, but another thing I noticed: The line of totality sweeps from west to east, so you should say that the 2009 eclipse went from India to the Pacific Ocean, not vice versa (and the diagrams should sweep that way too). I hope you can make this and the other corrections, because its concept is good!
I would subscribe..Unfortunately, it's not that simple
Nah, joking. Totally subbed :D
*simple
That nobody has commented this in 3 years is surprising.
This is perfect, thank you!! I really wanted a full, comprehensive explanation of all of the complexities of solar eclipses, as well as resources to learn more, and this video provided that perfectly!! I'm going to look at some of your other videos...
Great video Matt, but the music at the end goes up a bit too loud so we can't hear what you're saying.
Yes, good point. I made this on the road (chasing the eclipse all week!) and both sound and colour mixing leave much to be desired.
standupmaths no worries! Still found it fascinating! Also currently reading your book, it's great even if I don't understand what's going on most of the time xD
Unfortunately, it's not that simple. The gravitation of all bodies in the solar system (and indeed the universe), notably Jupiter, also slightly affect the orbits, precessions, and rotations of the Earth, Moon, and Sun. All three also experience tidal effects, and of course the Earth also experiences nutation (variation in its axial tilt). Admittedly, all these effects are smaller than those mentioned in the video, but they do collectively explain why it is practically impossible to accurately predict the dates of solar eclipses in the distant future.
this isnt to scale. unfortunately, it's not that simple.
Unfortunately, its not to scale
why??????
I got enough to keep me from being totally ignorant about the basics. Thanks Matt!
This time i will completely understand the maths in his video.....
Unfortunately its not that simple
Aaaaaarrrrrggghhhhh, the earth not being in the focal point of the ellipse in the animation is driving me craaaaaazzzzyyyyy!
Same here. It gave me feminism.
the 2024 north american total solar eclipse today is part of solar saros 139, exactly one saros cycle before the much-awaited 2042 total solar eclipse in my home country (the philippines) that's also in the same series
Please keep making videos. This one was fascinating!
Jayder845 Unfortunately, it's not that simple.
Ahem ... here is my theory: Matt spent time in Awstralya and that's where - and when, he acquired his sense of humour. ~~~
Unfortunately, it's not that simple.
@@eancarris3850 :(
I mean...he was born there, so...
Hi Matt. First of all congratulations for your videos. Just on thing: about 4 minutes in the video when you talk about the orbit of the moon around the earth, I believe there is a small discrepancy. The moon moves in fact on an ellipse, but the earth is not on the center of the ellipse but on one of the focus (or focci, don´t know the correct English word). So the nearest and farthest points should be on the vertices of the ellipse (aphelium and perihelium).
Yes; he acknowledges the ellipse misportrayal, with regrets, in the description above.
BTW, terminology:
aphelion, perihelion are farthest and nearest points of a body in *solar* orbit; for Earth orbit, the terms are:
• apogee, perigee.
The general terms are
• apoapsis, periapsis
. . and for other specific central bodies, the suffixes correspond to the name of the central body.
-helion is for the Sun;
-gee is for Earth;
-jove is for Jupiter;
-astron is for a general star;
etc.
Also, the plural of "focus" is "foci."
These are Latin, not really English, but adopted by English.
Love it, also love Matt's book.
That elliptical orbit diagram made Jebediah cry.
At 3:45, the earth should be at one of the foci of the ellipse and the closest and furthest points should be at the far right and left of the orbit (along the semi major axis).
Really liking this new upload schedule (lets be honest though, there really wasn't one before). Keep up the great work and high quality of vids mate!
Sadly this channel had been unloved for a very long time. But I'm finally giving it the attention it needs!
I really needed this video thank you very much for making it.
Thanks for a fine video. The diagrams were a little low-budget but they're better than I could do. One funny thing I noticed in the comments was how many people had gotten bent out of shape over the fact that the central objects weren't shown at a focus of the elliptical orbit. Meanwhile, I only spotted one person who noticed that the entire system was running backward! Viewed from north of the ecliptic, the planets revolve counterclockwise.
jeepien I've been scrolling through the comments looking for precisely this. It bugged me too. True, it's a completely arbitrarily, and perhaps Eurocentric, standard but it's still a standard. Look down on the north pole, Matt!!! Everything goes anti-clockwise (at least everything in this video).
2:13 that threatening "astronomical" comming ot get you!
I'd love to learn more about solar eclipses. Unfortunately, it's not that simple.
This was great! You should make more videos.
Yeah I totally agree
"Unfortunately it's not that simple!" is the new "But it gets worse!"
Never thought I'd will laugh watching a video about the math of an eclipse. Well done,mate. Well done.
Hey Matt, I'd love to see a video on how often the moon is in the same phase at the same time and same spot in the sky..
I believe it's something like 54 years and 34 days.
Perhaps the answer to your question depends on your definition of "same" or how exact that "same" needs to be.
3:37
"Rogue autofocus" again I guess 😂
So it turns out I've been subscribed since some time after this video went up, because this is the first time I watched it. prompted by Matt's tweet just ahead of the 2017 'US' total solar eclipse.
No, I'm not going back over the entire archive, at least not today.
"Unfortunately, it's not that simple..."
Okay, okay, okay, I get it, fine, time to go dust off the ol' copy of Numerical Recipies in C.
Does the shift in Saros Cycle up and down, left and right, guarantee with time and similar conditions, that ever square cm on earth will be covered with some solar eclipse at some point?
If the next eclipse is in 2045, then how come there were eclipses in 2015 when this came out, as well as more recently in 2017 and another happening soon in 2019? It seems that we have solar eclipses about every other year, not every 18, so what is happening here?
12:25
where is the early 70s (1971 as i recall) event immortalized in song
"you flew your lear jet up to nova scotia to see the total eclipse of the sun" ?
my wife and i were there to see it -
although we did not get there (from massachusetts) by lear jet.
Flat earthers take note. You need to include earth ROTATION in order for you to be able to use saros cycle to predict the future solar eclipses - 10:15
Exactly 💯!
3:35 Unforgiveable matt,
the earth should be in one of the foci of the ellipse.
I watched the 1999 total solar eclipse from Europe (Germany), and this coming summer I will watch the total solar eclipse from the US, where I currently work. That's one soros cycle, for the only two eclipses I will have ever watched. Of course, provided it won't be cloudy over North Carolina
The Matt Parker Drinking Game: Take a shot every time "Unfortunately, it's not that simple ..." is said.
One quibble: 3:36 you show the Moon's orbit as an ellipse with the Earth at the center of the ellipse. Actually the Earth is (roughly) at one focus of the ellipse so the Earth should be a bit to the right or left (close to the narrow part of the ellipse).
My astronomy teacher: "You want a big grade? Unfortunately, it's not that simple"
Very nice and interesting video! :D Hope to see many more like this! One thing, I believe when you talked about the 2009 eclipse, you meant to say that it started over India, no finished there :)
Well spotted! I completely messed that up. Nuts. I'll add a note or something…
Yeah well. In such a long video, one small thing will be wrong sooner or later :p
So then a Saros cycle can be defined as the length of time for predicting/observing similar and notable LUNAR,TERRESTRIAL, SOLAR occurrences? thank you, I just learned something today!
Although he already noted that nothing is to scale I think I should point out that the lunar orbit described is incorrect, with earth at the center of the elipse. It is actually at one edge of the elipse. A full orbit of the moon means only a single cycle in earth - moon distance.
speaking of which: matt! tell us about orbital mechanics please!
For god's sake Matt, I know youre a mathematician and not an astronomer, but even I (and Im neither of the two) know that the object being orbited sits in one of the focuses of the elliptical orbit of the object orbiting it. So the moon is closest when it's at the "pointy" end of the ellipse whose focus has the earth in it, and the farthest away when it's at the opposite end of that. Please reupload with this abomination fixed.
Not that simple. The center of gravity is inside Earth but not always inside one of the objects.
No mention of an annular eclipse which occurs when the Sun and Moon are exactly in line, but the apparent size of the Moon is smaller than that of the Sun. Hence the Sun appears as a very bright ring, or annulus, surrounding the dark disk of the Moon
Good point, I did feel like the video was a bit short!
Great video but I'm guessing you outsourced your closed captioning because at places like 7:35 or so, the captioner thought you said u.s. and lips. I'd hate to think you paid much for captioning. But again, great video, and I've been sharing this with several people over the years
How something you think should be simple is not that simple , but what a great job trying to explain it all 👍👏🏻👏🏻👏🏻👏🏻
But. ?! There was an August 2018 TE track in N. America which resemble the one you illustrated for August 2045. I'm confused how that works out with the Saros cycle.
I'm so glad Matt learned how to do his sound balance better in later years.
I wonder if he can do the math about the curvature! That would be interesting!
"Simply, it's not that unfortunate."
Alexandre Fyne why????????
THANK YOU SO MUCH. I have to write paper on this. Subscribed!
Yay n-body orbital mechanics! A much underappreciated field of mathematics and physics!
Did you get a good view of the eclipse Matt? I got a great one here near Swindon.
Thanks for posting this. It was very helpful!
The music was kinda loud, but great video!!! I was able to watch the partial eclipse from Spain, it was really cool!!
WHAT IS THE END MUSIC!! It's AMAZING!!
(great video btw :3)
standupmaths.bandcamp.com/track/stand-up-maths-theme
Wait how are there so many different saros cycles?
Awesome video!
How do you get the numbers with which you multiply the lunar months in order to get the saros value?
Thank you so much for the amazing videos!
How come your video doesn’t mention about the solar eclipse that happened this year in 2017?
He recorded it before the 2015 eclipse. He says so in the first few minutes of the video.
Think about it.
Year 2100, finally found a video explaining solar eclipses.
Would i as the sun not see the far side of the moon and not the earth facing side of the moon during a new moon phase.
If the Sun's pull on the Moon is twice that of Earth's pull on the Moon, how can you say that the Moon orbits the Earth? Isn't it more correct to say that both the Moon and Earth orbit the Sun, and they both revolve around a common barycenter (ie, center of mass)?
I saw one total eclipse in Budapest on August 1st 2008, though from my point of view it was like 99% eclipse actually. Because I was actually leaving back home on that day, and airport location didn't align perfectly for the total eclipse.
Thanks Matt. that was a brilliant video :D
One thing I always wanted to be sure about was the shadow of the Moon. Is every shadow we see on the Moon from the Earth ? or is it sometimes the shadow of the moon itself?
Not that simple bit didn't bother me as much as seeing the motions clockwise when it is all counterclockwise (earth and sun's rotations are and so are earth and moon's orbits too).
this saved my butt on a math project so than you sooo much!
Is this Franchise font, the one everyone seems to be using more and more now?
Just experuenced one this month
Nice video. Also young Matt. ❤❤
Why are all the animations rotating backwards.
And how could that get the egg heads?
Brilliant. Loved the insight. Genius.
amazing video hope more people get to watch it !!1
Video highlights:
2:13
3:19
5:22
6:30
7:09
7:20
10:41
14:17
You're welcome.
Thanks!
Doing this definitely was *not that simple* .
I really appreciate it.👍
Won't the 'which hemisphere is facing the sun' part also affect how high north or low south the eclipse is visible?
Oh, believe me Matt, there are a _lot_ of people who think the Moon is transparent!
No, I'm not kidding.
You drew the eclipse direction backwards...
PS, there is also a half Saros that maps solar eclipses to lunar ones and vice versa.
Unfortunately it's not that simple
How much bigger than the Earth is the Sun? I tried the maths, and came up with a figure of about 1,300,000. But I think that doesn't include the spaces between the Earths.
Does an eclipse at the north or south poll last the same length of time as one happening near the equator?
Awesome video
“Nothing in this video is to scale.” Your eye and your head is to scale.
Unfortunately, it's not that simple
The perpetual Jewish calendar (lunar, with an intercalanary month every two or three years) uses a "more traditional" average length of a lunar month, that is, new moon to new moon. This length is 29 days, 12 hours, 44 minutes, 3 1/3 seconds. (793/1080 of an hour).
An extra couple of seconds are a small price to pay for ease of use.
So are you telling me that the moon will not continue to orbit along the equator but rather in the total opposite direction?
13:36 by that point we will be crude oil😅😅😅
Well done mate/Dude!